Tolerance (Tolerance)

So, just to reiterate, the “Magic Wand” tool makes it’s selection region based on color, using a single click.
But why the “Magic Wand” tool to select color of a picture though, and not the others? Well, this has to do with the tolerance.
As an example I put an image taken with a gradient of colors (gradient), from black to white, separated by a red bar, in order to make everything clear.

I set the “tolerance” to 20, so when I click on the top bar with the gradient, Photoshop will select colors that are 20 levels higher and 20 levels lower than the ones (the pixel) where I clicked.
FYI: The gradient from black to white has 256 levels, where 0 is true for black and 255 applies to white. So if you start counting from 0 to 255, that makes 256.

Imagine the “tolerance” to 40, Photoshop will select colors from 40 levels higher to 40 levels lower than the ones (the pixel) where you clicked.

The checkbox “Anti-alias”makes the edges of your selection softer.
The checkbox “Contiguous” selects only the adjacent pixels.
Uncheck this option, then each pixel lying between our value (tolerance) in our image are selected.
The pixels do not need to lie side by side, as you can see the example below.

Finally, if we also check “Sample All Layers” on, Photoshop will take pixels from all the “layers” (layers) of our image.
More about layers in the next lesson.

Grow / Similar (Increase / similar)

Under the “Select” menu in the menu bar, we find the options “Grow” (Increase) and “Similar” (similar).
The only difference between these two commands is that, with “Grow”, only the adjacent pixels are selected and with “Similar”, it also selects the non-adjacent pixels.
So if we choose one of these in the menu bar, the selection will be expanded with the number of pixels that appeared in the “tolerance” box.

Featured Courses

• Downloading iPad Apps
• Lesson 1: Introduction to Publisher
• Lesson 65: File Formats